In Miles of Alleys, Chicago Finds Its Next Environmental Frontier

Monday

Nov 26, 2007 at 5:27 AM

Chicago’s effort to redo its alleys with sustainable road-building materials is one of the most ambitious public street makeover plans in the country.

CHICAGO, Nov. 25 — If this were any other city, perhaps it would not matter what kind of roadway was underfoot in the back alleys around town. But with nearly 2,000 miles of small service streets bisecting blocks from the North Side to the South Side, Chicago is the alley capital of America. In its alleys, city officials say, it has the paved equivalent of five midsize airports.

Part of the landscape since the city began, the alleys, mostly home to garbage bins and garages, make for cleaner and less congested main streets. But Chicago’s distinction is not without disadvantages: Imagine having a duplicate set of streets, in miniature, to maintain that are prone to flooding and to dumping runoff into a strained sewer system.

What is an old, alley-laden city to do?

Chicago has decided to retrofit its alleys with environmentally sustainable road-building materials under its Green Alley initiative, something experts say is among the most ambitious public street makeover plans in the country. In a larger sense, the city is rethinking the way it paves things.

In a green alley, water is allowed to penetrate the soil through the pavement itself, which consists of the relatively new but little-used technology of permeable concrete or porous asphalt. Then the water, filtered through stone beds under the permeable surface layer, recharges the underground water table instead of ending up as polluted runoff in rivers and streams.

Some of that water may even end up back in Lake Michigan, from which Chicago takes a billion gallons a year.

“The question is, if you’ve got to resurface an alley anyway, can you make it do more for you?” said Janet Attarian, the project’s director.

The new pavements are also designed to reflect heat from the sun instead of absorbing it, helping the city stay cool on hot days. They also stay warmer on cold days. The green alleys are given new kinds of lighting that conserve energy and reduce glare, city officials said, and are made with recycled materials.

The city will have completed 46 green alleys by the end of the year, and it has deemed the models so attractive that now every alley it refurbishes will be a green alley.

“It is now business as usual,” Ms. Attarian said.

But all these improvements come with a cost, and some people around Chicago have begun to wonder if a city that hardly recycles its trash and has a hard time keeping its trains and buses running should be spending money on fancy alleys.

Judy King, putting all her household refuse into one bag on Tuesday and tossing it into a bin in a green alley, said: “How do you decide where your priorities are? It’s a hard one. I’m bothered that there isn’t more recycling.”

The city has lately begun having serious talks about a comprehensive recycling program to replace the uneven guidelines now in place. But beyond recycling, it has a vast array of “green initiatives” that put it at the forefront of environmentally conscious cities.

This month, the city has begun two programs with financing from the Clinton Foundation intended to help owners of homes and businesses to modernize old, leaky buildings to reduce energy consumption.

The city also has an expedited permitting process for builders who use green techniques. Its garbage trucks and street sweepers have emission-control devices. In recent years, it has installed rooftop gardens to collect rainwater, planted a half-million new trees and created more than 200 acres of parks and open spaces intended to clean the air and add bits of beauty.

As for the alleys, the city says the cost of construction is offset by what it would have paid for maintenance and sewer improvements for the old ones.

The new alleys will require maintenance, too, so their pores do not get clogged, but, Ms. Attarian said, “I think they’re pretty price competitive.”

The city pays about $45 a cubic yard for permeable concrete, about $100 less than it did a year ago when concrete plants were just revving up production of the new material, but beyond that is the added expense of the stone filtration layer beneath the concrete. Ms. Attarian said ordinary concrete costs $50 or more a cubic yard. The products look pretty much the same.

With its history of heavy industry and bare-knuckled reputation, Chicago may not seem like the most likely city to exhibit environmental friendliness.

But Mayor Richard M. Daley has said that he wants to make Chicago a green model for the country. A few years ago, he was derided as a tree-hugger; now, other mayors are copying him. “Global warming is not a question,” Mr. Daley said in a recent press release. “How we deal with it is.”

Martin C. Pedersen, the executive editor of Metropolis, a magazine about urban living, said, “Recycling programs are all well and good, but the things that really move public policy and the industry are things like taxes and the building code.”

Mr. Pedersen said Mr. Daley had “made adjustments to both to encourage green building, and that’s a big deal.”

In the past several years, Chicago has also has built 90 miles of landscaped medians and refurbished more than 100 miles of streetscapes.

Michael David Martin, an associate professor and associate chairman of the Department of Landscape Architecture at Iowa State University, specializes in the study of alleys and neighborhoods. Mr. Martin praised what he called “more thoughtful alley design.”

“The alley is not only functional,” he said, “but an educational green landscape that is helping a city experiment with design and different ways to handle water.”

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